You have 4 years to sign a player before he can become a free agent. Waiting to sign a guy can result in just this. All the Preds can offer at this point is immediate playing time in the NHL. And, they're playing so well I'm not sure they want to mess around with the lineup. So, he goes UFA and can sign with the Leafs. I don't like it, but that's how the NHL rolls.
BTW - Did I mention how much I hate the offside review when the goal in question happens 20+ seconds after the questionable play? Urgh. Bettman sucks.